diff options
Diffstat (limited to 'arch/tile/kernel/smp.c')
| -rw-r--r-- | arch/tile/kernel/smp.c | 202 |
1 files changed, 202 insertions, 0 deletions
diff --git a/arch/tile/kernel/smp.c b/arch/tile/kernel/smp.c new file mode 100644 index 00000000000..782c1bfa6df --- /dev/null +++ b/arch/tile/kernel/smp.c @@ -0,0 +1,202 @@ +/* + * Copyright 2010 Tilera Corporation. All Rights Reserved. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation, version 2. + * + * This program is distributed in the hope that it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or + * NON INFRINGEMENT. See the GNU General Public License for + * more details. + * + * TILE SMP support routines. + */ + +#include <linux/smp.h> +#include <linux/irq.h> +#include <asm/cacheflush.h> + +HV_Topology smp_topology __write_once; + + +/* + * Top-level send_IPI*() functions to send messages to other cpus. + */ + +/* Set by smp_send_stop() to avoid recursive panics. */ +static int stopping_cpus; + +void send_IPI_single(int cpu, int tag) +{ + HV_Recipient recip = { + .y = cpu / smp_width, + .x = cpu % smp_width, + .state = HV_TO_BE_SENT + }; + int rc = hv_send_message(&recip, 1, (HV_VirtAddr)&tag, sizeof(tag)); + BUG_ON(rc <= 0); +} + +void send_IPI_many(const struct cpumask *mask, int tag) +{ + HV_Recipient recip[NR_CPUS]; + int cpu, sent; + int nrecip = 0; + int my_cpu = smp_processor_id(); + for_each_cpu(cpu, mask) { + HV_Recipient *r; + BUG_ON(cpu == my_cpu); + r = &recip[nrecip++]; + r->y = cpu / smp_width; + r->x = cpu % smp_width; + r->state = HV_TO_BE_SENT; + } + sent = 0; + while (sent < nrecip) { + int rc = hv_send_message(recip, nrecip, + (HV_VirtAddr)&tag, sizeof(tag)); + if (rc <= 0) { + if (!stopping_cpus) /* avoid recursive panic */ + panic("hv_send_message returned %d", rc); + break; + } + sent += rc; + } +} + +void send_IPI_allbutself(int tag) +{ + struct cpumask mask; + cpumask_copy(&mask, cpu_online_mask); + cpumask_clear_cpu(smp_processor_id(), &mask); + send_IPI_many(&mask, tag); +} + + +/* + * Provide smp_call_function_mask, but also run function locally + * if specified in the mask. + */ +void on_each_cpu_mask(const struct cpumask *mask, void (*func)(void *), + void *info, bool wait) +{ + int cpu = get_cpu(); + smp_call_function_many(mask, func, info, wait); + if (cpumask_test_cpu(cpu, mask)) { + local_irq_disable(); + func(info); + local_irq_enable(); + } + put_cpu(); +} + + +/* + * Functions related to starting/stopping cpus. + */ + +/* Handler to start the current cpu. */ +static void smp_start_cpu_interrupt(void) +{ + extern unsigned long start_cpu_function_addr; + get_irq_regs()->pc = start_cpu_function_addr; +} + +/* Handler to stop the current cpu. */ +static void smp_stop_cpu_interrupt(void) +{ + set_cpu_online(smp_processor_id(), 0); + raw_local_irq_disable_all(); + for (;;) + asm("nap"); +} + +/* This function calls the 'stop' function on all other CPUs in the system. */ +void smp_send_stop(void) +{ + stopping_cpus = 1; + send_IPI_allbutself(MSG_TAG_STOP_CPU); +} + + +/* + * Dispatch code called from hv_message_intr() for HV_MSG_TILE hv messages. + */ +void evaluate_message(int tag) +{ + switch (tag) { + case MSG_TAG_START_CPU: /* Start up a cpu */ + smp_start_cpu_interrupt(); + break; + + case MSG_TAG_STOP_CPU: /* Sent to shut down slave CPU's */ + smp_stop_cpu_interrupt(); + break; + + case MSG_TAG_CALL_FUNCTION_MANY: /* Call function on cpumask */ + generic_smp_call_function_interrupt(); + break; + + case MSG_TAG_CALL_FUNCTION_SINGLE: /* Call function on one other CPU */ + generic_smp_call_function_single_interrupt(); + break; + + default: + panic("Unknown IPI message tag %d", tag); + break; + } +} + + +/* + * flush_icache_range() code uses smp_call_function(). + */ + +struct ipi_flush { + unsigned long start; + unsigned long end; +}; + +static void ipi_flush_icache_range(void *info) +{ + struct ipi_flush *flush = (struct ipi_flush *) info; + __flush_icache_range(flush->start, flush->end); +} + +void flush_icache_range(unsigned long start, unsigned long end) +{ + struct ipi_flush flush = { start, end }; + preempt_disable(); + on_each_cpu(ipi_flush_icache_range, &flush, 1); + preempt_enable(); +} + + +/* + * The smp_send_reschedule() path does not use the hv_message_intr() + * path but instead the faster tile_dev_intr() path for interrupts. + */ + +irqreturn_t handle_reschedule_ipi(int irq, void *token) +{ + /* + * Nothing to do here; when we return from interrupt, the + * rescheduling will occur there. But do bump the interrupt + * profiler count in the meantime. + */ + __get_cpu_var(irq_stat).irq_resched_count++; + + return IRQ_HANDLED; +} + +void smp_send_reschedule(int cpu) +{ + HV_Coord coord; + + WARN_ON(cpu_is_offline(cpu)); + coord.y = cpu / smp_width; + coord.x = cpu % smp_width; + hv_trigger_ipi(coord, IRQ_RESCHEDULE); +} |